Dye-sensitized solar cells (DSCs) represent a viable means for harvesting solar energy to produce electrical power. Though a number of light harvesting dyes are in use, the search continues for more efficient and effective compounds to make commercially viable DSCs a reality. Computational methods have been increasingly applied to understand the dyes currently in use and to aid in the search for improved light harvesting compounds. Semiempirical quantum chemistry methods have a well-deserved reputation for giving good quality results in a very short amount of computer time.<br/><br/>The performance of PM6 is tested against a set of molecules whose geometries were optimized using a density functional theory (DFT) method and to reduce the differences between geometries optimized using PM6 and geometries optimized using DFT, the PM6 basis set parameters have been optimized for a subset of the molecules. It is found that it is sufficient to optimize the basis set for Ru alone to improve the agreement between the PM6 results and the DFT results. This new Ru basis set reduces the mean unsigned error in Ru-ligand bond lengths from 0.043 Å to 0.017 Å in a test set of 20 molecules.<br/><br/>Using this re-parameterized PM6 method, a large set of of Ru(II) centered light harvesters for DSCs is screened, including expanded cage structures, electron donating and withdrawing groups, and various anchoring groups. These results clearly demonstrate the value of using PM6 to screen DSC chromophores as well as the value of optimizing PM6 basis set parameters for a specific set of molecules.

Efficient computational screening tool for Ru(II) light harvesters

251st National Meeting (2016)

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